As is generally known, face masks have been designed to greatly reduce, if not prevent, the transmission of liquids and/or airborne contaminates through the face mask. In surgical procedure environments, such liquid sources include the a patient's perspiration, patient liquids, such as blood, and life support liquids such as plasma and saline. Examples of airborne contaminates include, but are not limited to, biological contaminates, such as bacteria, viruses and fungal spores. Such contaminates may also include particulate material such as, but not limited to, lint, mineral fines, dust, skin squames and respiratory droplets. A measure of a fabrics ability to prevent the passage of such airborne materials is sometimes expressed in terms of "filtration efficiency".
Many face masks were originally made of cotton or linen. Such face masks fashioned from these materials, however, permitted transmission or "strike-through" of various liquids encountered in surgical procedures. In these instances, a path was established for transmission of biological contaminates, either present in the liquid or subsequently contacting the liquid, through the face mask. Additionally, in many instances face masks fashioned from cotton or linen provide insufficient barrier protection from the transmission therethrough of airborne contaminates. Furthermore, these articles were costly, and of course laundering and sterilization procedures were required before reuse.
Disposable face masks have largely replaced linen face masks. Advances in such disposable face masks include the formation of such articles from totally liquid repellent fabrics and/or apertured films which prevent liquid strike-through. In this way, biological contaminates carried by liquids are prevented from passing through such fabrics. However, in some instances, face masks formed from apertured films, while being liquid and airborne contaminate impervious, are, or can become over a period of time, uncomfortable to wear. Furthermore, such face masks are relatively more costly than face masks containing only nonwoven webs.
In some instances, face masks fashioned from liquid repellent fabrics, such as fabrics formed from nonwoven polymers, sufficiently repel liquids and are more breathable and thus more comfortable to the wearer than nonporous materials. However, these improvements in comfort and breathability provided by such nonwoven fabrics have generally occurred at the expense of barrier properties or filtration efficiency.
One type of nonwoven fabric, a conventional spunbonded/meltblown/spunbonded (SMS) laminate, has been widely used in surgical garments, such as gowns and drapes, due to its excellent barrier properties and relatively low cost. To date, such SMS laminates have not been used in commercially available face masks due to their unacceptable breathability properties. Consequently, the search for face mask materials, which will provide liquid strike-through protection, breathability, and comfort at a relatively low cost, continues.
Therefore, there exists a need in the art for face masks and methods for making the same, which provide improved liquid strike-through protection, breathability, and comfort, as well as, improved filtration efficiency. Such improved materials and methods are provided by the present invention and will become more apparent upon further review of the following specification and claims.